The present invention is concerned with a method and an apparatus for making a knot with two end portions of flexible material wrapped around an article.
It is well known in the art that articles or products are wrapped with stretched film and that nothing else is required other than a brush to wipe the last tail. When stretched film is used, the static generated as it is stretched and the tacky material added to one side of the film make the tail stick to the layer previously applied. This method is appropriate when the article is shipped in a closed trailer or container but is inadequate when the product is shipped on an open trailer or stored outside because the tails are prone to getting loose as they are exposed to wind or bad weather.
In other applications, the articles are wrapped and then the tails are heat-sealed to previously applied layers of film. This well known technology is very popular. The seal is achieved by heating a heat pad which is brought in contact with the tail and previously applied layers of film. The film then melts in order to bond layers together. However, this method has some limitations. When the heat is applied to the film layers to create melting, holes can be created through all layers which remove the water proof protection of the product and/or can damage the product.
Known in the art, there is the U.S. Pat. No. 4,223,516, naming as inventor Marc G. VANSTEELANT, wherein there is described a knotter primarily for use with a crop baling machine. This knotter includes a rotatable twine holder for gripping the primary and secondary portions of twine and holding them in a side-by-side relationship extending along a predetermined path. A rotatable billhook is mounted adjacent to the twine holder and positioned to intersect the predetermined path. Drive means interconnecting the twine holder and billhook rotate the two elements in timed relation such that during a first cycle of the billhook the twine portions are positioned thereabout, and during a second cycle of the billhook a knot is tied therein.
Also known in the art, there is the U.S. Pat. No. 5,240,295 naming as inventor Donald R. SPENCER, wherein there is described a device which facilitates tying knots, particularly blood knots joining sections of a leader for a fishing line. The device includes a flexible frame having a base and left and right legs which project away from the base, there being a gap between the two legs. The frame carries a post which projects from the base into the gap intermediate the two legs and may be extended or retracted and even withdrawn. The legs carry winders which rotate about a common axis. Each winder has a hollow interior, a winding arm located at the gap, and a gripping sleeve remote from the gap. Lines or lengths of leader are inserted through the hollow interior of each winder and engaged with the winder arm of the other winder. When the winders are rotated, their arms twist the lines around each other, but the post forms a separation or opening in the wound region of the lines. The tag ends of the lines are inserted through the separation to produce a blood knot which is pulled tight.
Also known in the art, there is the U.S. Pat. No. 5,088,270 naming as inventor Werner K DIEHL, wherein there is described a heat seal assembly and method for securing stretch-film wrapped about a package, which assembly grasps and aligns two strips of roped film wraps, heats adjacent faces of the roped film sections and thereafter compresses these heated faces to weld them to each other and secure the film wrap about the package.
Also known in the art, there is the U.S. Pat. No. 6,195,968 naming Yanick MAROIS et al. as inventors, wherein there is described an apparatus for wrapping a load with a flexible wrapping material which prevents the flexible material from unwrapping itself after the load has been wrapped. The apparatus includes a first finger and a gripper for positioning a portion of a first rope supplied by the supplying means at a predetermined location. Once the load has been wrapped, a second finger and a guide wheel are provided to position a portion of a second rope supplied by the supply means at the predetermined position. The first and second ropes are fastened together at the predetermined position, and a portion of the second rope is cut downstream of the predetermined position.
Also known in the art, there are the following U.S. patents which describe different apparatuses and methods for making a knot: U.S. Pat. Nos. 3,570,553; 3,752,517; 3,915,483; 4,420,177; 4,765,082; 4,795,201; 4,872,240; 5,197,217; 5,236,232; 5,728,109; 5,787,691; 5,802,810; 5,878,555; 5,971,447; and 6,143,006.
A drawback with systems or methods of the prior art is that none of them is concerned with a method of making a knot with two end portions of flexible material wrapped around an article in a simple and efficient manner.
An object of the present invention is to provide a method and an apparatus for making a knot with two end portions of flexible material wrapped around an article in a manner that is simpler and more efficient than those provided in prior art.
It is also an object of the present invention to provide an apparatus and a method for making a knot with two end portions of flexible material wrapped around an article in an automated manner so that the apparatus and method can be applied to successive articles without any manual intervention of an operator.
According to the present invention, there is provided a method of making a knot with first and second rope-shaped end portions of flexible material wrapped around an article, comprising steps of: (a) guiding the end portions along a predetermined path; (b) (i) nipping the first end portion at a first point of the predetermined path, (ii) nipping the second end portion at a second point of the predetermined path, and (iii) nipping the second end portion at a third point of the predetermined path; (c) cutting the second end portion between the second and third points to obtain a free end thereof; (d) moving the end portions to obtain a loop; (e) releasing the first end portion from the guiding of step (a) to obtain a free end thereof; and (f) inserting the free ends into the loop to form and tighten the knot.
According to the present invention, there is also provided an apparatus for making a knot with first and second rope-shaped end portions of flexible material wrapped around an article, comprising: a controllable holder for holding a free end of the first end portion; controllable guides for guiding the end portions along a predetermined path; first controllable nippers for nipping the first end portion at a first point of the predetermined path; second controllable nippers for nipping the second end portion at a second point of the predetermined path; third controllable nippers for nipping the second end portion at a third point of the predetermined path; a controllable cutter for cutting the second end portion between the second and third points to obtain a free end thereof; first controllable moving means for moving the end portions to obtain a loop; and second controllable moving means for moving the free ends into the loop to form and tighten the knot.
The objects, advantages and other features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given for the purpose of exemplification only with reference to the accompanying drawings.